Hard disk drive (HDDs) for a file server or other type of computer are often mounted, in a vertically or horizontally stacked array, in a rectangular sheet metal “cage” structure which may be disposed within the computer housing or externally thereto. For operational convenience and flexibility, each disk drive is typically “hot plug” connected within the cage. This type of electrical connection permits any of the supported disk drives to be removed and re-installed within the cage without disturbing the operation of the other disk drives.
To effect this desirable hot plug connection of each of the disk drives, each disk drive is typically supported on a carrier structure which is slidably and removably insertable into the cage to mate an electrical connector carried on a rear portion of the drive or its carrier structure with a corresponding electrical connector on a back plane circuit board suitably supported at the rear interior side of the cage.
There are various types of HHDs such as SATA (Serial Advanced Technology Attachment) HHDs, PATA (Parallel Advanced Technology Attachment) HHDs, SAS (Serial Attached SCSI) HHDs, FC (Fibre Channel) HDDs, and the like. An increasing problem associated with the carrier support of disk drives removably mounted in cage structures or the like is a mixed mode operation (e.g., when a FC HDD is improperly placed into a receiving slot of a chassis where a SATA/SAS HDD should have been placed) which may cause HDD read/write timing problems, data corruption, and/or data loss.
Thus, it would be desirable to provide a hard disk drive (HDD) system and keying method, which may prevent a mixed-mode operation of HDDs.